Is freezing food foolproof? There is a science to frozen storage capacity and repeated thawing

In the hot summer, food preservation is an important line of defense for food safety. Nutritionists point out that although refrigerator freezers have become an indispensable helper in the kitchen, don't think that putting food directly into the refrigerator is foolproof. Improper frozen storage will make food more prone to spoilage and cause waste, so people must not underestimate this.

Li Wanping, a professional nutritionist at Rongxin Clinic, pointed out that we should have the correct concept of food preservation in summer. Although various foods have a shelf life, the shelf life also varies due to different animal textures and ingredients. For example, well-preserved pork or beef can be kept in the freezer for several months without spoiling, but seafood can only be kept for 1 to 2 weeks at most and should be consumed.

Food should not be kept frozen for too long

Take aquatic products such as fish and shrimp as an example. The temperature of the growth environment is relatively low, so most of the bacteria attached to them are also resistant to low temperatures. The temperature of home freezing cannot ensure that it can kill the bacteria and parasites in them. Even in the freezer, it is still easy to destroy the flavor and nutrients of the food itself. Therefore, fish and shrimp should not be kept in the freezer for too long.

As for meat, the current freezing temperature of household refrigerators is approximately between -12 degrees Celsius and -19 degrees Celsius, and it is often turned on and off, which makes it easier for the temperature to rise. This temperature still has the potential to activate parasites and most bacteria. Long-term freezing will not only cause the meat to lose its taste and flavor, but also make it impossible to maintain a constant low temperature, casting a shadow on the freshness and safety of the food.

Nutritionist Li Wanping (pictured) stressed that food preservation is an important line of defense for food safety during the hot summer. (Photo provided by Rongxin Clinic)

Repeated thawing of food increases risk

Nutritionist Li Wanping emphasized that many people mistakenly believe that repeatedly thawing food after freezing will not affect the freshness of the food itself. In fact, freezing food does not kill bacteria. Especially during the repeated thawing process, the food itself is more likely to breed bacteria due to increased temperature and changes in humidity, increasing the safety risk of the food itself.

Take meat as an example. The best situation is to buy it and eat it immediately. However, if you cannot finish it in one go, it is recommended that you cut a large piece of meat into small portions that can be eaten each time and store them. , take it out in batches to avoid repeated freezing, which will reduce the food flavor and is not easy to cause bacterial contamination.

5 tips for refrigeration and freezing to keep you healthy

1. Separate food: cooked food on top, raw food on the bottom. If you plan to eat the food you buy within a few days, place it in the cooler area of ​​the refrigerator. If you plan to store it for a long time, you should put it in the freezer of the refrigerator.

2. Cut and pack: The whole piece of meat can be divided into appropriate small pieces in advance and placed in food boxes with lids or double-layer plastic bags. Eat it as needed without affecting other foods. It can also increase the freezing speed of meat and ensure good meat quality.

There are some tips for storing food, and it is important to store them separately.

3. Defrosting tips: Do not rush and do not put quick-frozen meat in a pot or boiling water in an attempt to thaw it quickly. It is best to take it out of the freezer the day before cooking and place it in the refrigerator (6--8℃) to thaw slowly. The ice crystals in the juice between the meat cells will gradually dissolve and seep into the cells, restoring the meat to its fresh state. When cooked, it tastes the same as fresh meat.

4. Storage at appropriate temperature: Generally, many microorganisms can still survive at low temperatures, so the storage time should not be too long. Generally, livestock meat can be stored for 3 to 7 days at 1°C to -1°C, and can be stored for a longer time at -10°C to -18°C, usually 1 to 2 months.

5. First in, first out: You need to pay attention to old goods stored in the refrigerator. The storage date and food contents can be written on the outer packaging of frozen food. Otherwise, it may be difficult to tell what the food is like after being frozen for a long time, the food will lose water and taste bad, and the fat and protein will gradually change and affect the quality. Meat food should not be stored in a home freezer for more than 3 months, and fish food should be stored for a shorter time.

Do not fill the refrigerator with food too full as this will increase the temperature and cause bacteria to grow, affecting the freshness of the food.

Use a refrigerator to avoid overcrowding

Nutritionist Li Wanping emphasized that the best way to ensure food safety is to put the food in the refrigerator within 2 hours after consumption; but if the room temperature is higher than 32°C, it must be stored in the refrigerator as soon as possible within 1 hour. It is not necessary to wait until the food is completely cooled before putting it in the refrigerator.

At the same time, many people think that food classification is done by tying it up with a plastic bag, covering the soup pot with a lid, or wrapping it with plastic wrap. In fact, if raw and cooked foods are not properly packaged and sealed, and refrigerated and frozen separately, the chance of bacterial cross-contamination will increase.

[Nutritionist's Tips]:

Do not fill the refrigerator too full, because if it is too full, the temperature inside the refrigerator will increase and the freshness of the food will be shortened. Therefore, the refrigerator can only be filled to 2/3, which is about 70% of the capacity, to facilitate cold air circulation to maintain the coldness and ensure the safety of fresh food.